Currently, the touch control technology is mainly divided into five types: the resistive type, the capacitive type, the surface acoustic wave type, the optical type (infrared rays) and the electromagnetic type. The touch control technology is mainly applied to the public field such as the ATM, the ticket affairs, the educational system, the cash register, etc., since it was invented in 1974. The resistive touch control technology has always been the mainstream touch control technology. However, the touch control technology is applied to the personal mobile device, since APPLE released the i-phone in 2008. This enables the touch control technology to be promoted to the capacitive touch control technology. Although the cost of the resistive touch control technology is low, the resistive touch control technology is still unpopular since it is not wear-resisting and has a slow response speed and a low transmittance. However, although the surface acoustic wave touch control technology and the optical touch control technology have good precision and durability, they are too costly to become the mainstream technologies. Although the electromagnetic touch control technology has good sensitivity and durability, it occupies a large volume, is difficult to assemble, and needs a dedicated electromagnetic pen. Therefore, the capacitive touch control technology will continue to be the mainstream touch control technology in the next few years.
Currently, the capacitive touch technology is divided into two types: the surface capacitive touch technology and the projective capacitive touch technology. The surface capacitive touch technology has the advantages of a large area, a low cost and low energy consumption; however, the disadvantages thereof are that the corners and edges of the touch panel have low precision and are more sensitive to electromagnetic induction. The projective capacitive touch technology enhances precision through the x-axis and the y-axis sensors; however, the disadvantage thereof is that the process for manufacturing the x-axis and the y-axis sensors is more complicated. But even so, since lots of factories invest time and money in developing the x-axis and the y-axis sensors, the costs thereof have been greatly reduced. For example, the price of the i-pad 2 is far cheaper than that of the i-pad 1. Therefore, in recent years, the application of the projective capacitive touch technology is still continually increased. For the current capacitive touch technology, the cover for the touch panel is usually made of glass. Although the polyethylene terephthalate (PET) is used, the glass is still the mainstream in the market due to the consideration of durability. However, since the strength of the glass is poorer, the tempered glass is introduced to the application of the capacitive touch technology. The tempered glass is manufactured by soaking the glass in the chemical medicinal liquid to strengthen the glass. Then, the tempered glass is cut according to the requested size by the customer to serve as the cover for the touch panel. Finally, the tempered glass is bonded to the sensor. However, after the tempered glass is cut, tiny holes will be generated at the edge portion thereof. The tiny holes will lead to fracture in the subsequent bonding process. Although someone proposes cutting the glass first and then soaking it in the chemical medicinal liquid, the cost will be greatly increased.
Please refer to FIG. 1, which shows the structure of a conventional projective capacitive touch panel 10. The conventional projective capacitive touch panel 10 includes a cover 100, optical glues 101, 102, a sensing module 106 and a display panel 108. The sensing module 106 includes sensing layers 103, 105 and a sensing substrate 104. The sensing module 106 is bonded to the cover 100 via the optical glue 101. Through the optical glue 101, the sensing layer 103 is bonded to the cover 100. The sensing module 106 is bonded to the display panel 108 via the optical glue 102. Through the optical glue 102, the sensing layer 105 is bonded to the display panel 108.
The cover 100 is made of glass. The sensing layers 103, 105 are formed on the sensing substrate 104 via the conventional semiconductor process, thereby completing the manufacture of the sensing module 106. Besides, after the sensing module 106 is manufactured, it needs to be bonded to the cover 100 via the optical glue 101. In this way, the process needs one more step. Moreover, the hardness and the mechanical strength issues will be generated when the cover 100 is made of glass.
Please refer to FIG. 2, which shows the structure of a conventional projective capacitive touch sensor 20. The conventional projective capacitive touch sensor 20 includes a cover 200, a specific pattern 202, optical glues 203, 204, a glass touch sensor 207 and a display panel 210. The glass touch sensor 207 includes a sensing control chip 206 and a glass substrate 208.
The sensing control chip 206 is made of the indium tin oxide (ITO). The sensing control chip 206 is constructed on the glass substrate 208 via the conventional semiconductor process, thereby forming the glass touch sensor 207. The glass substrate 208 is bonded to the display panel 210 via the optical glue 204 so that the glass touch sensor 207 is bonded to the display panel 210. The cover 200 is usually made of glass or the PET film. The specific pattern 200 can be formed at the lower portion of the cover 200. The sensing control chip 206 is bonded to the specific pattern 202 via the optical glue 203 so that the glass touch sensor 207 is bonded to the cover 200.
Please refer to FIG. 3(a), which shows the structure of a control chip 30 of a conventional projective capacitive touch sensor. The control chip 30 includes a glass substrate 300, ITO transparent conductive films 320, 360 and an insulating layer 340. Firstly, the ITO transparent conductive film 320 is manufactured on the glass substrate 300 via the film process. Then, an x-axis transparent conductive net 310 is manufactured in the ITO transparent conductive film 320. Next, the insulating layer 340 is manufactured on the ITO transparent conductive film 320, and then the ITO transparent conductive film 360 is manufactured on the insulating layer 340 via the film process. Finally, a y-axis transparent conductive net 330 is manufactured in the ITO transparent conductive film 360. The insulating layer 340 is for isolating the x-axis transparent conductive net 310 from the y-axis transparent conductive net 330.
Please refer to FIG. 3(b), which is a top view of FIG. 3(a). When the control chip 30 is touched by the finger of the user, the capacitance value of the touch area 380 is changed. Therefore, through the x-axis signal scan and the y-axis signal scan, and the noise suppression for the scanned x-axis signal 32 and the scanned y-axis signal 34, the coordinate of the touching area 380 can be determined.
The above-mentioned conventional covers 100, 200 are made of glass. Besides, the sensing module 106 needs to be bonded to the cover 100 via the optical glue 101, and the glass touch sensor 207 needs to be bonded to the cover 200 via the optical glue 203. Moreover, the hardness and the mechanical strength issues of the glass are to be overcome. Currently, the surface of the cellphone of the user is usually pasted by a paster to prevent scrape, or is plated by the fluoride to prevent greasiness. Besides, using the glass substrate 208 to serve as the substrate of the glass touch sensor 207 will meet the issue that the volume thereof is unable to be reduced. For ensuring the strength of the conventional projective capacitive touch panel 10, the thickness of the cover 100 cannot be too thin. Accordingly, the thickness of the entire conventional projective capacitive touch panel 10 is thicker. Based on the above, it is shown that the covers 100, 200 made of glass are to be improved.
In order to overcome the drawbacks in the prior art, a touch panel structure is provided. The particular design in the present invention not only solves the problems described above, but also is easy to be implemented. Thus, the present invention has the utility for the industry.